The purpose of this project is to examine the manner in which immunological mechanisms may contribute to diseases of the central nervous system (CNS) in humans. These studies included examination of the cellular immune response to viruses which can commonly affect the CNS and which may be related to the induction of autoimmune processes of the nervous system. In addition, these studies have examined the immune response, and in particular, the cellular immune response to antigens of the nervous system such as myelin basic protein and proteolipid protein. The emphasis in these studies has been on identifying differences which may occur in patients with diseases of the CNS such as multiple sclerosis as compared to healthy individuals. Particular attention has been paid to the influence of genetic makeup on both the induction and effector phases of the immune response to viruses as well as antigens of the CNS. Focus has been placed on identification of cytotoxic T cells specific for both viruses or antigens of the nervous system. In addition, the capacity of cells of the CNS to process and present antigens to immune T cells has been examined in order to help understand how immunological mechanisms are induced within the nervous system.